Roll out new diff algorithm

[hediet]

The new diff algorithm is 70% slower than the current one, but provides better results. 95% percentile is 600ms, which is fine.
50% of stable users already use the new diff algorithm.

Potential blockers:

• Uncaught Error: Assertion Failed Error: Assertion Failed at v (vscode-file://vscode-app//out/vs/base/worker/workerMain.js#editorWorkerService:13:8295) at A (vscode-file://vscode-app//out/vs/base/worker/workerMain.js#editorWorkerService:16:125394)  #188077 (happens very rarely)
• Diff editor shows funny word alignments #188060
• Diff Editor V2: No Notification When Document Has Only Whitespace Change #188202

See also:

• https://github.com/microsoft/vscode-internalbacklog/issues/4379

Verification steps:

• Go to settings and verify the default of "diffEditor.algorithm" is "advanced"